Thursday, January 24, 2013

Taking away the mystery

I want to share something with you. If you have taken one of my sharpening classes you may have seen this already. If not, this is for you.

When I teach sharpening I try to make it very clear that the media is unimportant, it's all technique. Sure, some media is faster than others, some media is more expensive. But the proper techniques will produce a great edge regardless of your choice of media. I do not intend to teach those techniques in a blog post. Everyone that has taken one of my classes has heard me say, "It's fun to watch an expert but you will learn faster if the expert watches you."

My method of sharpening uses two or three abrasives. The coarsest of which is used shaping. Shaping is adjusting a bevel or fixing a nick. The medium abrasive does the actual sharpening, I prefer the term honing since sharpening if, to me, the entire process. The finest grit is used to polish the edge. Attend the class for details or, if there are sufficient requests, I'll do a video here that will clear things up.

Grid seems too nebulous a term to me. To make the discussion easier in my classes I researched the size of the abrasive of various media. The first charts I made just showed the grit to abrasive size of the various media. After that I determined reasonable abrasiveness for each operation and reformatted the charts with that information. I determined that I use abrasives courser than 22 microns for sharping, 22 to 10 for honing, and finer than 10 for polishing.

There are some "exceptions" to the rules. For example, Shapton 1000 grit stone cuts so fast that it works fine for honing and some shaping. Another exception is the fact that sandpaper that is fine enough for polishing is quite expensive, therefore I recommend stropping rather than polishing with sandpaper.

So, for your use here are the charts I include in my sharpening notes. Feel free to ask questions/make comments below.


Grit to Abrasive size
Shapton
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
1,000
14.7
4,000
3.63
8,000
1.84
16,000
0.92
30,000
0.49


Norton Water
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
220
65
360
36
600
22
800
16
1,000
14
1,200
11
1,500
9.2
2,000
7.5
4,000
6
8,000
3
15,000
0.5


Diamond Stones
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
diamond
127
extra coarse
65
coarse
43
fine
22
extra fine
11


Arkansas
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
soft
22
hard translucent
6


India
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
coarse crystolon
127
coarse India
97
medium crystolon
78
medium India
53.5
fine crystolon
45
fine India
29
extra fine India
22




Sandpaper
Coarse (Shaping)
Medium (Honing)
Fine (Polishing)
120
116
150
96
180
78
220
60
240
53.5
280
43
320
36
360
29
400
23
600
16
700
14
800
12.6
1,000
9.2
1,500
8.4
2,000
6